DOES PALEOLIMNOLOGICAL EVIDENCE SUPPORT THE FISH REMOVAL PROJECT IN EAST POND?

The frequency of nuisance algal blooms in East Pond, Smithfield Township, Maine has been increasing in the past two decades. Meanwhile, the trophic status of the hydrologically-linked, North Pond, has remained relatively constant, even though both ponds have similar morphometry and geology. In the spring of 2007, a biomanipulation project involving the removal of white perch, yellow perch, and black crappie in East Pond was started to reverse the trend of decreasing water quality. The purpose of our study was to provide a longer-term assessment (>100 years) of the trophic status of these two lakes through the use of chemical and biological components in lake sediments. A 45-cm sediment core was collected from each pond in January 2008. The cores were sectioned in 0.5-cm increments, dated by ²¹⁰Pb analysis, and analyzed for isotopic carbon and nitrogen, diatom assemblages, and chemical phosphorus speciation. The chemical speciation data suggests that both ponds contain roughly equal amounts of phosphorus in the sediment. However, East Pond has more potential for internal loading of phosphorus than North Pond because there are higher concentrations of labile and reducible phosphorus in the top few centimeters of sediment. At the time of submission, the results from the diatom assemblages and isotopic work are still pending.